Way OT programming question
Jerry McAllister
jerrymc at clunix.cl.msu.edu
Mon Aug 2 07:49:05 PDT 2004
>
> I've been muddling through some of the source files for FreeBSD
> 5.2.1-RELEASE, and I've noticed that a large number of .c files
> in /usr/src have something similar to below in them:
>
> #ifndef lint
> #if 0
> static char sccsid[] = "@(#)cat.c 8.2 (Berkeley) 4/27/95";
> #endif
> #endif /* not lint */
> #include <sys/cdefs.h>
> __FBSDID("$FreeBSD: src/bin/cat/cat.c,v 1.29 2003/04/30 17:40:28
> obrien Exp $");
>
> 1) Isn't 'if 0' always negative?
In a boolean usage like above, yes. Anyway, FALSE usually gets
defined to be 0. So, the above piece of code is disabled - sort
of commented out, so to speak.
> 2) What is the __FBSDID line doing?
Looks like it sets or checks some version information. Guess I could
look it up, but then, so could you.
////jerry
>
> --
> Thanks,
>
> Josh Paetzel
> _______________________________________________
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